Most modern UPS systems do not include the internal transformers that were present in earlier designs. This evolution has increased efficiency while decreasing the weight, size, and raw materials consumption of UPS systems. In the new transformerless UPS designs, the transformers are optional and can be placed in the best location to achieve a required purpose. In older designs, transformers we...

Abstract—Voltage level must be raised in order to deliver the produced energy to the consumption zones with less loss and less cost. Power transformers used to raise or lower voltage are important parts of the energy transmission system. Power transformers used in switchgear and power generation plants stay in human's intensive habitat zones as a result of expanding cities. Accordingly, noise l...

In order to reduce the volume and size of distribution power transformer, precise and extended controlling of transformer output, the conventional transformers are replaced by intelligent universal transformers (IUTs). In this paper, an IUT, typical of Iran national grid, with the voltage ratio of 20kV:380 V is designed and simulated. Regarding the IUT implementation, a cascaded H-bridge invert...

In this paper, a new model has been presented to determine the number of spare transformers and their locations for distribution stations. The number of spare transformers must be so that they need minimum investment. Furthermore, they must be sufficient for replacing with transformers that have been damaged. For this reason, in this paper a new purpose function has been presented to maximize p...

This paper presents the effects of instrument transformers connection points on the measured impedance by distance relays in the presence of Flexible Alternating Current Transmission System (FACTS) devices with series connected branch. Distance relay tripping characteristic itself depends on the power system structural conditions, pre-fault operational conditions, and especially the ground ...

This paper presents a novel approach based on the back-propagation neural network (BPNN) for the insulation diagnosis of power transformers. Four epoxy-resin power transformers with typical insulation defects are purposely made by a manufacturer. These transformers are used as the experimental models of partial discharge (PD) examination. Then, a precious PD detector is used to measure the 3-D ...

Understanding the behavior of network forensic devices is important to support prosecutions of malicious conduct on computer networks as well as legal remedies for false accusations of network management negligence. Individuals who seek to establish the credibility of network forensic data must speak competently about how the data was gathered and the potential for data loss. Unfortunately, man...

The study introduces the detailed sequence of operations necessary to determine the selfand mutual inductances of power transformers from numerically simulated open-circuit and bucking experiments. Parameters of a welding style transformer are compared to those of a normal step-down transformer of equivalent ratings. The investigation identifies the different patterns of magnetic flux circulati...

In the refinement calculus, monotonic predicate transformers are used to model specifications for (imperative) programs. Together with a natural notion of simulation, they form a category enjoying many algebraic properties. We build on this structure to make predicate transformers into a denotational model of full linear logic: all the logical constructions have a natural interpretation in term...

estimating the final price of products is of great importance. for manufacturing companies proposing a final price is only possible after the design process over. these companies propose an approximate initial price of the required products to the customers for which some of time and money is required. here using the existing data of already designed transformers and utilizing the bayesian anal...